1、 Reference numberISO/IEC TR 18037:2008(E)ISO/IEC 2008 TECHNICAL REPORT ISO/IECTR18037Second edition2008-06-15Programming languages C Extensions to support embedded processors Langages de programmation C Extensions pour supporter les processeurs intgrs ISO/IEC TR 18037:2008(E)PDF disclaimer This PDF
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6、the requester.ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel.+41 22 749 01 11 Fax +41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO/IEC 2008 All rights reserved ISO/IEC TR 18037:2008(E)ISO/IEC 2008 All rights reserved iiiContents Page 1 SCOPE.1 2 NO
7、RMATIVE REFERENCES.1 3 CONFORMANCE.1 4 FIXED-POINT ARITHMETIC.2 4.1 Overview and principles of the fixed-point data types.2 4.1.1 The data types.2 4.1.2 Spelling of the new keywords.3 4.1.3 Rounding and Overflow.4 4.1.4 Type conversion,usual arithmetic conversions.5 4.1.5 Fixed-point constants.6 4.1
8、.6 Operations involving fixed-point types.7 4.1.7 Fixed-point functions.9 4.1.8 Fixed-point definitions .11 4.1.9 Formatted I/O functions for fixed-point arguments.11 4.2 Detailed changes to ISO/IEC 9899:1999.12 5 NAMED ADDRESS SPACES AND NAMED-REGISTER STORAGE CLASSES.37 5.1 Overview and principles
9、 of named address spaces.37 5.1.1 Additional address spaces.37 5.1.2 Address-space type qualifiers.37 5.1.3 Address space nesting and rules for pointers.38 5.1.4 Standard library support.39 5.2 Overview and principles of named-register storage classes.39 5.2.1 Access to machine registers.39 5.2.2 Na
10、med-register storage-class specifiers.39 5.2.3 Ensuring correct side effects via objects allocated in registers.41 5.2.4 Relationship between named registers and I/O-register designators.41 5.3 Detailed changes to ISO/IEC 9899:1999.41 6 BASIC I/O HARDWARE ADDRESSING.49 6.1 Rationale.49 6.1.1 Basic S
11、tandardization Objectives.49 6.2 Terminology.49 6.3 Basic I/O Hardware addressing header.51 6.3.1 Standardization principles.51 6.3.2 The abstract model.52 ISO/IEC TR 18037:2008(E)iv ISO/IEC 2008 All rights reserved 6.4 Specifying I/O registers.54 6.4.1 I/O-register designators.54 6.4.2 Accesses to
12、individual I/O registers.54 6.4.3 I/O register buffers.55 6.4.4 I/O groups.56 6.4.5 Direct and indirect designators.56 6.4.6 Operations on I/O groups.57 6.5 Detailed changes to ISO/IEC 9899:1999.58 ANNEX A-FIXED-POINT ARITHMETIC.65 A.1 Fixed-point datatypes.65 A.1.1 Introduction.65 A.2 Number of dat
13、a bits in _Fract versus _Accum.68 A.3 Possible Data Type Implementations.69 A.4 Rounding and Overflow.70 A.5 Type conversions,usual arithmetic conversions.71 A.6 Operations involving fixed-point types.71 A.7 Exception for 1 and 1 Multiplication Results.72 A.8 Linguistic Variables and unsigned _Fract
14、:an example of unsigned fixed-point.73 ANNEX B-NAMED ADDRESS SPACES AND NAMED-REGISTER STORAGE CLASSES.74 B.1 Embedded systems extended memory support.74 B.1.1 Modifiers for named address spaces.74 B.1.2 Application-defined multiple address space support.75 B.1.3 I/O register definition for intrinsi
15、c or user defined address spaces.76 ANNEX C-IMPLEMENTING THE HEADER.78 C.1 General.78 C.1.1 Recommended steps.78 C.1.2 Compiler considerations.78 C.2 Overview of I/O Hardware Connection Options.79 C.2.1 Multi-Addressing and I/O Register Endianness.79 C.2.2 Address Interleaving.80 C.2.3 I/O Connectio
16、n Overview:.81 C.2.4 Generic buffer index.81 C.3 I/O-register designators for different I/O addressing methods.82 C.4 Atomic operation.83 C.5 Read-modify-write operations and multi-addressing cases.83 C.6 I/O initialization.84 C.7 Intrinsic Features for I/O Hardware Access.85 ISO/IEC TR 18037:2008(E)ISO/IEC 2008 All rights reserved vANNEX D-MIGRATION PATH FOR IMPLEMENTATIONS.86 D.1 Migration path for implementations.86 D.2 implementation based on C macros.86 D.2.1 The access specification method
